Spoonman

My first posted question for all you experts .

I just purchased a 99 Cherokee. I have not been able to get it to my house yet, so I don't have a lot of technical info about the jeep yet so I guess I'm just looking for some preliminary trouble shooting ideas and opinions on this thing.

The kid I purchased it from said that it over heated on him one day and actually had over heated a couple times that day on him so he parked it.
He replaced the thermostat,plugs and wires from what he says but it still over heats.
He told me it is "knocking" so before I agreed to buy it I went to hear the so called knock and the engine don't even make a ticking noise when running so I decided to buy it.
It runs real rough so one of the cylinders is missing but other than that the engine actually sounds real good.The po had somebody look at it and said he thought one of the valves might be sticking.
I'm thinking head gasket since I had a vehicle in the past with a bad hg and the jeep is acting the same exact way except for the continued over heating.

The only tech info I can offer at this point is that it is a 1999,with the 4.0L V6, and 196k miles, as far as I know it is just a cherokee I'm not sure about sub model.
Po says the oil level has not gone up so this may disprove my head gasket theory.
When I seen it running I did not notice much smoke coming from the exhaust however the exhaust did smell pretty funky.

I guess my question even though I don't have much info to offer about the specs of the jeep is:

1)Initial ideas of what the problem might be?

2)do the jeeps have any known faults that would cause over heating issues?

3)I'm also a bit concerned about a chance of a warped or cracked head, so how hard is it to do this?

4) I'm really kinda betting on the blown head gasket, how hard is it to change on the jeep 4.0?

I know it is such a noobish thing to post such questions with out having more specific info on the vehicle but I should have the jeep at my house this weekend hopefully and will be able to give more needed info.

If you guys could just kinda toss your ideas of what it could maybe be that would be great.

I'm hoping I get it home and the distributor rotor is burnt or something lol but I probably wont get so lucky .

tjwalker

The 4.0 is an inline 6 cylinder, not a V6

If this were in my garage, the first test I would run on it would be a compression test on all cylinders. That might tell the story. Low pressure on two adjacent cylinders and you have your head gasket diagnosis. If that is the case, the head comes off, head goes to a shop where they can check to see if it is straight and magnaflux it/check for cracks and determine if all else is good. Money well spent here, you MUST not just slap a gasket on it and hope for the best!

This is all a do-able project for sure, but give yourself extra time if you've never done a head before and be SURE to read a procedure about this before starting!

Then you still have the overheating to contend with. Lots of suspects here including radiator, water pump, thermostat, radiator cap, etc. If this stuff is old and the engine checks out okay except for some top end repair, I would just replace all of it while it is in the shop. The parts really aren't that expensive if you are doing it yourself. Then you'll know the cooling system is up to snuff.

Cherockee

If this XJ is a late '99 model with the 0331 head then you probably do have the cracked head problem.

I think your best bet, with that many miles, is to pull the head first off. Fix/replace it, replace valve seals, check the cam and cylinder walls while you've got it off and start from there.

Spoonman

Thanks for the replies.
Sorry tjwalker I know its not a v6 lol it was late when I posted and wasn't thinking strait, I just wanted to get the post up and get to sleep .

I have replaced head gaskets before just not an jeeps lol I know the basic concept is the same but I am new to jeeps all together. I have never owned or worked on a jeep.

I am kinda planning on having to pull the head and having it re worked but once I get it home I will do all the little check overs before jumping to a larger job like the head. I learned the hard way many times to check all the small simple things before.
I just have my fingers crossed at this point that it will be something stupid and simple lol.

Thanks again for all your input guys,I'll keep an update of my progress.

Spoonman

I almost forgot. I will be towing the jeep home my self, I have never towed a 4x4 and was curious about which end I need to tow the jeep from. I don't want to damage anything. I am probably going to be using a car dolly to get it home.

I know you want to tow a vehicle while not engaging its drive wheels so a front wheel drive would be towed from the front wheels.
I assume that you also don't want to tow with the steer wheels bearing all the weight etc from towing so lol I'm kinda at a loss of how to tow the jeep.

Uhaul says the drive shaft needs to be disconnected . Although this isnt a huge problem to do, Its winter time lol.

I will be towing it about 20-25 miles.

2Evil4U

assuming it's a 4x4, just put the xfer case in neutral and you should be good to go.

tjwalker

I have seen no evidence of the 99 having an 0331 head, and have done some pretty extensive research on this to satisfy myself.

I have sent pm to a couple of people who had discussed this possibility, but nobody can verify anything.

I believe that the 0331 head was only found in 00-01 XJs.

If there is any question, get a rag out and wipe off the lip of the head on the drivers side about halfway down. With a good light, you can read the casting number.

Spoonman

So whats with the 0331 heads? Do they crack easy or something?

tjwalker

Check out this thread. After taking the hour to read it, you'll understand....

http://www.jeepsunlimited.com/forums...d.php?t=391831

Cherryokee

Where are you located? Add to your profile.

If close to Boston (within an hour) then I'd be willing to help you.

Spoonman

Ok thanks tjwalker I will look at that link.


Cherryokee,I live in NY, I will try to figure out how to edit my profile in a bit .

I got the jeep to my house tonight, I decided to just pay to have a flat bed deliver it. I keep trying to be cheap and do things like towing my self and usually in the long run its just easier to pay to have things like that done.

I will be looking into the jeep maybe tomorrow and post any findings or questions.
Thanks for all the replies guys.

Spoonman

In case anybody is interested, I have not really found anything out as I cant get my jeep started. I have not had much time to spend on it but am hoping to have decent weather this weekend to mess with it.

I did replace the distributor cap and rotor as that was needed
I pulled the first 4 plugs and tried to look in the cylinders. The plugs are new but were pretty dirty, the number 4 plug was completely bridged with what looked like grease and oil which blew off with air, I think it was just wet no solid deposits.

I could see some liquid of some sort in the number 4 cylinder and stuck a wire into the cylinder which came out wet.There is also a good amount of liquid in the intake. I cant tell what it is since it is dark in color probably due to the intake being filthy but I assume it is coolant.

I will hopefully be able to do a compression test this weekend and will post the results.

Cherockee

May be worth pulling all the plugs and turn the engine over a few times to help pump out any contaminents. Then do a compression test and let us know what you find.

Cherryokee

Spoonman, sorry dude, it would take me a New York hour to get there from Boston if that hour was made out of sixty New York minutes, but my Jeep's no time machine. Oh well - coulda', shoulda', woulda'...

Sounds like it's time for brain surgery (i.e., may need to pop open the head)!

Spoonman

LOL yea sounds like Ill be doing the head gasket, I just want to get some compression readings first though. I know they will be off but it will still give me an idea of the condition of the bottom end of the engine.

Do you suppose that the liquid in the intake manifold is coolant? Thats really the only thing I can imagine would be able to get in there in bulk.